Monopolar devices have been well-known to cauterize vessels and cut tissue depending on the frequency used. Monopolar devices operate by using the patient as the ground pathway to complete the circuit. However, this arrangement is not efficacious in certain surgical applications, as the energy moves through the entire body.
Bipolar cautery devices have also been employed to coagulate and cauterize tissues. Bipolar cautery devices utilize two electrodes, with the intent to localize energy between the two poles of the electrodes, thereby minimizing energy delivery to adjacent tissues and structures. More specifically, during electrosurgical procedures, a high-frequency electric current is generated and applied to biological tissue. The electric current heats the tissue to coagulate blood vessels to reduce or stop bleeding.
However, one of the issues with bipolar cautery devices is the ability to control the amount of energy to be delivered to accomplish the desired coagulation. Less energy is required the closer the electrodes are positioned together. In certain instances, for example in neurosurgical applications, it is desirable to deliver as low an amount of energy as possible when attempting to mitigate a bleeding vessel to prevent tissue damage, especially around critical structures in the brain. However for bi-polar cautery devices where the poles are at a fixed distance apart from one another, the amount of energy for a given application can be too great for the intended target, thereby leading to undesirable collateral tissue damage.
One type of bipolar coagulation device includes bipolar forceps, whereby the two electrodes may be selectively varied in distance from one another by the user. However, care must be taken to ensure that the electrodes do not contact each other directly, as when this happens, no energy is being delivered to the intended tissues and no coagulation/cautery occurs to the intended tissue. In contrast, if the electrodes are spaced too far apart, more energy is required to achieve coagulation, which can lead to collateral tissue damage. Thus, there is a need to provide some degree of control over the spacing of the electrodes, while still permitting variability to address the specific surgical applications.
It is also known to irrigate the surgical field while using a cautery device. For example, in some known arrangements, a fluid delivery device, separate from the coagulation device, is arranged to drip irrigant into the surgical field. However, this arrangement has some drawbacks in that it is difficult to position the irrigation supply to be directly over the area of interest, and often requires an additional person in the surgical field to deliver the fluid. Moreover, the additional irrigation delivery device often impedes visibility of the surgical field. For example, in minimally invasive microsurgical procedures, the surgical corridor and the subsequent target is relatively small, thus an external drip presents delivery challenges for the additional person and visibility challenges for the surgeon whom is using the coagulation device on the intended tissue to be coagulated due to too many instruments and hands in the surgical field simultaneously. As a result, visualization at the surgical site may be compromised.
In other known devices, a separate fluid delivery conduit may be positioned above or below the forceps to provide irrigation to the surgical field. While these arrangements avoid the need for an additional person to hold and direct the irrigation supply, the fluid delivery conduit outlet is not positioned close enough to the cautery tips, but instead proximal of the electrode tips such that the fluid is not delivered to the surgical site, where the tips of the electrodes are positioned.
In addition to fluid delivery, during a surgical procedure, it is often necessary to clear the surgical field to enable the surgeon to properly visualize the field. More specifically, at times during a surgical procedure it is necessary to aspirate blood and irrigant out of the surgical field. While separate aspirating wands are known, the use of a separate surgical tool in a narrow surgical corridor can be problematic.